The present invention relates to a method for attaching an electrical connector to a base material. More particularly, it pertains to a method for attaching a flexible electrical connector to a movable contact finger and a stationary terminal without degrading the flexibility of the connector or the mechanical strength of the contact finger and the stationary terminal.
Electrical contactors commonly have flexible, electrically-conductive connectors that operatively connect a movable contact finger and a stationary terminal. U.S. Pat. Nos. 4,804,933 and 4,849,590, which are both assigned to Brown Industrial Gas, Inc., disclose switch modules that incorporate flexible connectors. Prior methods for attaching the flexible connector to the contact finger and stationary terminal have included brazing, resistance brazing, resistance welding and plasma arc welding. All of these attachment methods generate a relatively large heat affected zone surrounding the weld zone that disadvantageously anneals the connector. Annealing softens a portion of the connector which leads to erratic flexing and buckling, and eventual breaking, of the connector. The heat also anneals the contact finger and the terminal which lessens the mechanical strength of these components. A further disadvantage with such methods is that the relatively large heat affected zone changes the resistance of the components. Other methods, such as ultrasonic welding, are limited because large connectors cannot be welded due to transducer power limitations.
A further drawback associated with prior methods relates to the arrangement of the flexible connector relative to the base materials, such as the movable contact finger and the stationary terminal. The flexible connector is positioned generally parallel to each base material and welded in place. This necessitates that the contact finger and the stationary terminal be positioned a substantial distance apart in order for the connector not to flex dramatically or flex adjacent the connections.